In the pediatric population, constipation is the chief complaint in about 3% of all pediatric outpatient visits; as many as 25% of referrals to pediatric gastroenterologists are for children with constipation. The majority of these children have a form of functional constipation, referred to as FFR or functional fecal retention. The primary objective of this trial is to characterize the pharmacokinetics of a single oral dose of 0.03 mg/kg prucalopride in pediatric subjects aged less than/greater than 4 to less than/greater than 12 years with FFR. This dose corresponds to an adult dose of .15 - 2.0 mg of prucalopride. The secondary objective is to evaluate the safety and the tolerability (adverse experiences) of a single oral dose of prucalopride solution, 0.03 mg/kg, given to pediatric subjects with FFR. No efficacy will be evaluated in this trial.